Method for consolidating impermeable soils and pile provided thereby as fitted with spaced apart enlargements

ABSTRACT

A method for consolidating impermeable soils. Mixes of binding materials are pressure injected into the subsoil through pipes alternately formed of blind wall sections and apertured wall sections, through the latter said binding mixes laterally pressing the soil and forming therein consolidation enlargements which are spaced apart from one another along the vertical axis of the guiding tube.

United States Patent Taranto Dec. 10, 1974 [54} METHOD FOR CONSOLIDATING2,025,948 12 1935 Jorgensen 61 /36 R IMPERMEABLE SOILS AND PILE2,196,211 4/1940 Hartman 61/36 R 3,099,911 8/1963 Turzillo 61/53.6PROVIDED THEREBY AS FITTED WITH 3,184,924 5/1965 3 Staunau 6l/56.5SPACED APART ENLARGEMENTS 3,492,823 2/1970 Lamberton 61/53.6 [76]Inventor; Rosanna Taranto, Corso Vittorio 3,518,834 7/1970 Gnaedinger eta1 61/36 R Emanuele Napoli, Italy FOREIGN PATENTS OR APPLICATIONS [22]Filed: Apr, 19, 1972 703,654 2/1954 Great Britain 61/35' [21] Appl245600 Primary Examiner-W. C. Reynolds Assistant Examiner-Alex Grosz[30] Foreign Application Priority Data Attorney g or Firm-Bacon & ma

Dec. 14, 1971 Italy 40450/71 [57] ABSTRACT I v [52] US. Cl 61/35,61/53.52, 61 /53.6 A m h f r c n olida ing imp rmeable soils. Mixes [51]Int. Cl E02d 3/04, EOZd 3/08, EOZd 5/34 of binding materials arepressure injected into the sub- [58] Field of Search 61/35, 36 R, 53.68,53.52, Soil through pipes alternately formed of blind wall sec- 61/53 6tions and apertured wall sections, through the latter said binding mixeslaterally pressing the soil and form- [56] References Cit d ing thereinconsolidation enlargements which are UNITED STATES PATENTS spaced apartfrom one another along the vertical axis 1,265,164 5/1918 Barry 6l/53.6ofthe guldmg tube 1,404,925 1/1922 Blumenthal 61/36 R 3 Claims, 4Drawing Figures METHOD FOR CONSOLIDATING IMPERMEABLE SOILS AND PILEPROVIDED THEREBY AS FITTED WITH SPACED APART ENLARGEMENTS Methods areknown for subsoil consolidation by means of pressure injecting propermixes (such as cement, chemical mixes and the like).

It is also known that said methods are based on intergranularpenetration of the mixes into the soil mass or body; however, when thesoil granules are very small (clayey, slimy, muddy and the like soils),said penetration would be impossible and the operation would beineffective. In other terms, soils having a very low per- The object ofthe present invention is a method for tamping and hence consolidatingthe above soils, which method is preferably carried out by staticaction, therefore free of shakings, vibrations or other violentperturbations to the soil. Obviously, where a dynamic action isadvisable, nothing prevents from using it.

This method is characterized by providing tamping piles provided withenlargements in the soil, as obtained by injecting mixes of pressurebinding materials into the subsoil through pipes alternately formed ofblind wall sections and apertured wall sections, through the latter saidbinding mixes laterally pressing the soil and forming thereinconsolidation enlargements which are vertically spaced apart from oneanother along the axis of the guiding pipe.

By way of not limiting example, an arrangement embodying the inventionfeatures is shown in the accompanying drawing, in which:

FIG. 1 is a vertical section through the soil after the method has beencarried out;

FIG. 2 is a vertical section on an enlarged scale relative to FIG. 1,showing a portion of the operating tube as formed of blind wall tubesections and apertured or anyhow permeable sections;

FIG. 3 is a cross-section taken along line 3'3 in FIG. 2; and

FIG. 4 is a cross-section taken along line 4-4 in FIG.

First, a borehole is drilled of a depth suiting the problem beinginvolved. A so-called operatingtube is fitted in this hole 10, theoperating tube comprising blind sections 11 and widely aperturedsections 12, the latter being externally coated with a protective shell13 of jute cloth and/or plastic material, or rubber in one or morelayers.

The gap 10' between hole 10 and tubes 11 and 12 can be filled with moreor less resistant binding mixes. This filling can be effectedseparately, or by supplying the low pressure mixes through saidoperating tube.

The liquid mixtures, as statically supplied to the operating tube, forexample by means of a pressure pump, will provide at said aperturedsections 12 pressure enlargements 14 which are more or less extendeddependent on the pressure rates. Thus, rather than stressing the soilthrough narrow passages as in ordinary injections, the mixtures willinstead be effective as distributed on extended areas, such as thosecorresponding to the apertured tube sections 12.

On completion of a first tamping operation with building up of stillreduced size pressure enlargements 13 and following a suitableconsolidation such that partial hardening of the supplied mixes occurs,the operating tube ll, 12 is washed or scavenged (or drill again wherethe consolidated mix should have become too hard) and therefore readiedfor a further operation and so on, which operation can be repeated foran indefinite number of times, obviously increasingly raising thepressure rates and obtaining further more extended enlargements 14. Bysuch operations and where the soil should exhibit some permeability, anintergranular penetration of the mixes would also be provided inaddition to the formation of tamping enlargements (the effect of whichin connection with the soil consolidation requires no discussions);conversely, where impermeable soils are concerned, only a tampingenlargement would be formed. However, it should be pointed out that inslimy-clayey or quite muddy soils, substantially impervious toconventional injections, the tamping effect will be provided at theexpense of porosity water ejection, which water is forced to migrateoutwardly of the operation zone.

This effect is the more stressed as the higher the volume ofsoil pressedby the enlargements 14. At the same time, due to the building up of saidenlargements 14, a soil chamber or quite a substantial soil raising canbe obtained under a suitable pressure.

For example, an embankment founded on soft grounds can be stabilized tothe design dimension without requiring to cause or tolerate settlements,as in the case of sand drainages, vibrofloatation, etc.

Among the system advantages, the capability should be added ofindefinitely repeating the process.

The above described device also lends itself to carry out actualfoundation piles, wherein the tube acts as a reinforcement and thecasting, as effected by cement conglomerate, has extensions at the baseand along the trunk which are thoroughly tamped against the soil.

What I claim is:

1. A method for consolidating impermeable clay or muddy soils whichcomprises:

1. forming a borehole in the soil extending into the impermeablesubsoil;

2. inserting into said borehole a rigid tube formed of alternating solidand apertured wall sections having a plurality of apertures therein,said tube being externally coated with a casing formed of deformablematerial in the areas of said apertured wall sections;

3. pressure injecting a hardenable binding material into said tube andthrough said apertured-wall sections thereof into said deformablecasing, whereby said deformable casing is deformed and laterally pressesagainst the subsoil, thereby providing a plurality ofvertically-separated consolidation enlargements along the tube in theareas of said apertured wall sections thereof;

consolidate the same. 2. A method as claimed in claim 1, wherein saidcasing is made ofjute cloth.

3. A method as claimed in claim 1, wherein the mixture is staticallyintroduced into the tube and hence the soil, by means of a pressurepump. l= k

1. A method for consolidating impermeable clay or muddy soils whichcomprises:
 1. forming a borehole in the soil extending into theimpermeable subsoil;
 2. inserting into said borehole a rigid tube formedof alternating solid and apertured wall sections having a plurality ofapertures therein, said tube being externally coated with a casingformed of deformable material in the areas of said apertured wallsections;
 3. pressure injecting a hardenable binding material into saidtube and through said apertured wall sections thereof into saiddeformable casing, whereby said deformable casing is deformed andlaterally presses against the subsoil, thereby providing a plurality ofvertically-separated consolidation enlargements along the tube in theareas of said apertured wall sections thereof;
 4. permitting saidbinding material to at least partially harden and washing or scavengingsaid tube and repeating said step (3) at least once to further enlargethe consolidation enlargements provided in said step (3); and 5.permitting the binding material in said tube and in said consolidationenlargement to completely harden and leaving said tube in tHe soil tothereby consolidate the same.
 2. inserting into said borehole a rigidtube formed of alternating solid and apertured wall sections having aplurality of apertures therein, said tube being externally coated with acasing formed of deformable material in the areas of said apertured wallsections;
 2. A method as claimed in claim 1, wherein said casing is madeof jute cloth.
 3. A method as claimed in claim 1, wherein the mixture isstatically introduced into the tube and hence the soil, by means of apressure pump.
 3. pressure injecting a hardenable binding material intosaid tube and through said apertured wall sections thereof into saiddeformable casing, whereby said deformable casing is deformed andlaterally presses against the subsoil, thereby providing a plurality ofvertically-separated consolidation enlargements along the tube in theareas of said apertured wall sections thereof;
 4. permitting saidbinding material to at least partially harden and washing or scavengingsaid tube and repeating said step (3) at least once to further enlargethe consolidation enlargements provided in said step (3); and 5.permitting the binding material in said tube and in said consolidationenlargement to completely harden and leaving said tube in tHe soil tothereby consolidate the same.